Details

Autor(en) / Beteiligte

• Kim, Jihn E.
• Carosi, Gianpaolo
• Physical Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California 94550

Titel

Axions and the strong CP problem

Ist Teil von

• Reviews of modern physics, 2010-03, Vol.82 (1)

Ort / Verlag

United States

Erscheinungsjahr

2010

Quelle

American Physical Society Journals

Beschreibungen/Notizen

• Current upper bounds on the neutron electric dipole moment constrain the physically observable quantum chromodynamic (QCD) vacuum angle |{theta}|(less-or-similar sign)10{sup -11}. Since QCD explains a great deal of experimental data from the 100 MeV to the TeV scale, it is desirable to explain this smallness of |{theta}| in the QCD framework; this is the strong CP problem. There now exist two plausible solutions to this problem, one of which leads to the existence of a very light axion. The axion decay constant window, 10{sup 9}(less-or-similar sign)F{sub a}(less-or-similar sign)10{sup 12} GeV for an O(1) initial misalignment angle {theta}{sub 1}, has been obtained from astrophysical and cosmological data. For F{sub a}(greater-or-similar sign)10{sup 12} GeV with {theta}{sub 1}<O(1), axions may constitute a significant fraction of the dark matter of the universe. The supersymmetrized axion solution of the strong CP problem introduces its superpartner the axino, which might have affected the evolution of the Universe significantly. The very light axion (theory, supersymmetrization, and models) using recent particle, astrophysical, and cosmological data, and present prospects for its discovery is reviewed here.